Fertilizer



Patented av 27, 1924.

NITED ,5

r T E i JOB MOB/TEN AUGUST STILLESEN, or CHICAGO, ILLINOIS.

FERTILIZER.

m Drawing. Application flleii April 12, 1917, Serial No. 161,393. Renewed October 1a, 1923.

To all whom it may concern:

Be it known that I,=JoB' MORTEN AUGUST STILLESEN, a subject of the King of Norway,

residing at Chicago, in the county of Cook. 5 and State of Illinois, have invented certain 'new' and useful Improvements in Fertilizers,

of which the following is a specification.

This invention relates to fertilizers-and has particular reference to the production '10 of phosphate fertilizer materials both with and yvithout combined nitrogen. I I

The phosphoric acid contained in natural .phosphate rock or in other' phosphate compounds, bone phosphate, etc., is generally in the insoluble form of tricalcium phosphate C21 (P0 and is commonly converted by treatment with sulphuric acid into super phosphates, accord-- or acid monocalcium n mg to the reactlonz or to dlCBclClllIIlPhOSPhflllB.

I If lime (CaO), or a lime containing material such as results upon treating calciumfcarbide with nitrogen in a furnace (CaCN +CaO), be added to monocalcium i tricalcium phosphate, or a mixture of both,

according to the following reactions:

Hydrated lime (CaO H acts similarly. Lime nitrogen directly from the nitrogen furnace contains upwards of 20% of lime, or if hydrated, upwards of 25% of CaO I-I Dicalcium phosphate is partially available as plant food, although not easily soluble in water, but soluble in a solution of citric acid, and is'therefore termed in the trade citrate soluble phosphate. It is available by. plants because carbon dioxide contained in Water in the soil re-acts-to producemonoca'lclum phosphate, as follows:

Y Dicalcium phosphate, if heated, partially materials;

reverts to tricalcium phosphate, and becomes to that extent non-available, as follows (6) 4CaHPO +heat= In View of the foregoing, it has been impracticable to combine phosphate and lime nitrogen fertilizer materials together, owing to the reversionof the available phosphates to the unavailable form in the presence of hydrated or unhydrated lime.

The objects of this invention are to provide an improved'processwhereby combined fertilizer materials composed of available phosphates and lime nitrogen can be cheaply produced, and also containing in the preferred embodiment, useful calcium carbon-.1

ate instead of comparatively useless calcium sulphate. The invention comprises the novel process, as well as the novel products, which latter are useful either' directly as fertilizers, or for compounding with other I have discovered unavailable phosphates can be rendered available, by treatment with carbon dioxide and water, as follows:

(7) Ca (PO,) +2CO' -1-2'H O:

I 2 CaH (PO -|-CaCO or citric acid soluble phosphate acts according to the-following:

The carbon dioxide can be either gaseous,

solid, or liquid, or can be in a condition of- J expansion from solid or liquid to gas. The dicalcium phosphate can be obtained either by mixing the tricalcium phosphate with monocalcium phosphate, as follows 2- or (3) above, or as folerable for use alone or with limenitrogen by reason of their calcium carbonate content, over available phosphates as heretofore made by the sulphuric acid process. Other advantages will later appear. I

Having. obtained available phosphates,

uch as dicalcium phosphate, or monocalcium phosphate, as above described, the next step is the combination thereof, with lime nitrogen. v V I In my Patent 982,311, is disclosed a process f treating calcium carbide with nitrogen and carbin dioxide, whereby the lime present as such is transformed into carbonate, with consequent elimination of the objectionable caustic qualitles of ordinary calcium cyanamid. Subsequently, I discovered a modification "of such process whereby the transformation of the lime; is effected by solid or liquid carbon diox de, or

with carbon dioxide gas under expansion,

whereby the lime in' lime nitrogen. mixture is transformed into either normal, or one v or more basic calcium carbonates, according to the quantity of carbon dioxide, and Water, as follows: I pp 11 1 CaO+CO :-CaCO or a basic carbonate, as

1 12 egcaO-ifCO zcaCO -cab, or another basic carbonate:

1 (13) 3CaO-1-2'CO,:2CaCO .GaO,etc.

Ifwater be present, the lime is changed into one or more normal or basic hydrated carbonates, according to the quantity of carbon dioxide, as follows,

a eoaoo ohonmm,

ide. Calciumcarbonates resist the action of phosphoric acid, because the :carbonates must first be broken up and. the carbon dioxide driven off before the lime and phosphoric acid can combine, It is therefore apparent that an available phosphate can .be readily mixed with limenitro-gen containing normal or basic carbonates, or both,

without reversion to unavailable phosphate.

When such a carbonate containing compound is in the soilf the carbon dioxide set free by phosphoric acid, or soil acids, will react with any unavailable or water 'insoluble phosphates according to reaction (5) above, converting it into the-more soluble and available compound.

The insoluble unavailable tricalcium phos phate can be mixed with calciummarbido and some unchanged calcium carbide.

1 and carbon dioxide, the reaction is tion is neeaavo and heated in the "lime nitrogen furnace. The nitrogen is absorbed by the calcium carbide according to the Well-known reaction, while the carbon set free will have areduc ing action on the tricalcium phosphate. lPhe reducing action can be ass'sted by adding silicon, or a flux,,such as silica. (SiO A product is thereby obtained comprising lime nitrogen, lime, tricalcium phosphate or partly reduced tricalcium phosphate, carbon, By treating this product with water and'carbin dioxide gas, the lime is converted into carbonate, and the calcium phosphate rendered available, elther as monoc alcium phosphate, or dicalcium phosphate, or both. Instead of tricalcium phosphate, the dicalcium and monocalcium phosphate can be used for mixing with the calcium carbide.

Also tricalcium phosphate or dicalcium phosphate can be mixed withraw lime nitrogen containing lime, some carbide, etc., a'nd treated with carbon dioxide andwater, converting the lime into carbonate, and the unavailable phosphate into either of the W available forms of super or citrate soluble phosphate, or partly of either.

If monocalcium phosphate is mixed with raw lime nitrogen and treated with water (16) CaCN Ca0 Cal-1411),), CG H tg -CacN +CaCO,+CaI-L(PO,),+

The water added in this reaction either mo evaporates or combines with the carbonates of lime. 1

If dicalcium phosphate is used, the reac- If tricalcium phosphate is treated with raw lime nitrogen, the reaction is:

If treated lime nitrogen, such as above de. scribed Where the lime has been converted into carbonate be used with tricalcium phosphate, the reaction is: 1 v

If dicalcium phosphate be used with carbonated lime nitrogen, the reaction is:

'20 2CaHPO +CaCN +CaCOS+CO H O Call (P0 2 OaClV ZCaCO,

If tricalcium phosphate is mixed with I commercial calciunr carbide, the reaction is: 125 (21) Ca (l 0 +CaC +Ca0 +2N Whichisthen treated with water and carbon dioxide gas according to reaction (18). I 3

A particular advantage of this invention is present where lime nitrogen just as received from the nitrogen furnace is to be combined with available phosphates. "Commercial calcium carbide usually contains free lime (CaO), which lime is overburned and does not change in the nitrogen furnace. The theory of the formation of calcium carbide is that lime is melted by the high heat of the carbide furnace and dissolves carbon, but there always remains in the commercial carbide some lime, which cools and crystallizes. Such lime is called overburned, and is hard and very difficult to slake. It also combines with difficulty with carbon dioxide. Moreover, lime nitrogen comes from the nitrogen furnace in lumps, so that the lime present unless pulverized, will not as readily combine with carbon dioxide. There will also be some free carbide in raw lime nitrogen.

My preferred procedure is to pulverizc the raw lime nitrogen mixture and then sprinkle and mix with water. The amount can vary from twice to three times the amount necessary to slake the lime present and remove the carbide, to as low as 5% to 10% of this amount. By reason of the lime being over-burned in whole or in part, it does not easily slake as the water enters very little into combination with this over-burned lime. By now-exposing moistened raw lime nitrogen to carbon dioxide in solid form, or passing from solid to gas, or under expansion, the carbon dioxide immediately and readily combines with lime, the reaction between the lime and the carbon dioxide gas giving 0E heat, and evaporating the water. If after the treatment, uncombined water remains, it is driven ofi by heating below 100 (1, so as to prevent the formation of dicyandiamid (C N H and calcium hydroxide. My product is in small grains ready for market without either crushing or briqueting. The expanding as absorbs heat, so that the temperature can e so controlled as to prevent decomposition of cyanamid. More gas is taken up if more water be added, thus enabling one or more carbonates to be obtained. If lumps of lime nitrogen are wet with water, the water is absorbed, and if then treated with carbon dioxide under expansion, the gas will penetrate the lumps, combine with the lime, drive off the water, and the lumps will fall to pieces, giving as a final marketable product, carbonated lime nitrogen in granulated form. This avoids pulverizing or briqueting the final material,

and also avoids the pbj ectionable dusty qualities of ordinary lime nitrogen. This material, being without calcium oxide, does not revert available phosphates, and 1 consider that the failure to heretofore prevent reversion of available phosphates has been ,due to the presence of free or slaked lime in the gas which exists when the expanding gas reacts with the water treated lime, under the stated conditions of temperature, vis

viva of the gas, its kinetic energy, etc. The

exact explanation of the results I have discovered yet remains to be given, because chemical investigations in low temperatures,

-with compressed gases, or gases going di-- rectly from solid to gaseous state, are, scien tifically considered, still in their infancy. From the above, it will be understood that any of the available calcium phosphates can be used for mixing with a lime nitrogen fertilizer, and that the resulting product may contain any, or a mixture of two, or of all three, of the calcium phosphates, andthat the calcium phosphates can be mixed either before the treatment with nitrogen gas, or before the treatn'ient with carbon dioxide gas, or after the treatment with carbon dioxide gas. Inthe foregoing specification, by raw lime nitrogen is meant the product obtained after treating commercial calcium carbide with nitrogen, comprising calcium cyanamid, normal and over-burned. lime, and usually some calcium carbide, while by treated orcarbonated lime nitrogen is meant such product as results when the free lime of raw lime nitrogen has been converted, as for instance,'into one or more normal, or basic carbonates, or hydrated basic carbonates of calcium, or a mixture of all. By carbonate, is intended to be included basic, or hydrated carbonates, as well as normal carbonate, such as the calcium compounds mentioned herein. It is also to be understood that the foregoing reactions and materials are intended to betypical or explanatory, and not as limitations upon the invention except as specified in the appended claims, and within the range of permissible equivalents.

The fertilizer material resulting from this invention will contain, besides nitrogen and phosphates, more or less carbon dioxide gas in the form of carbonates. gas set free in the soil from any of these compounds will greatly increase the fertilizer value of the material. The carbon dioxide gas set free in the soil either by the Carbon dioxide fix acids in the soil, or by part of the phosphoric acid, Will Work on the silicious compounds of potash in the soil, and cause the potash to be dissolved. It Will also have a dissolving Faction upon carbonates of lime and magnesia, and on the different oxides of iron and manganese, whereby these compounds, otherwise hardly available, will be conveyed to the plants.

Having thus described my invention, I declare that what T claim as new and desire to secure by Letters Patent is:

1. The process of producing an available phosphate which consists in treating an unavailable phosphate with condensed carbon dioxide and water.

2. The process which consists in treating tricalcium phosphate with condensed carbon dioxide and water.

3. The process which consists in treating tricalcium phosphate and lime nitrogen containing either lime or calcium hydroxide with carbon dioxide and water.

4. The process which consists in treating a phosphate with carbon dioxide in a conmea re dition of expansion, water and raw lime nitrogen.

9. The process which consists in treating a calcium phosphate with carbon dioxide in a condition of expansion, Water and raw lime nitrogen.

10. The process which consists in treating a calcium phosphate with carbon dioxide in a condition of expansion, water, lime and lime nitrogen.

11. The process which consists in treating tricalcium phosphate with carbon dioxide in a condition of expansion, water, and raw lime nitrogen.

12. The process which consists in treating tricalcium phosphate and calcium carbide mixture with nitrogen and heat, and then with water and with carbon dioxide.

13. The process which consists in treating tricalcium phosphate and calcium carbide mixture with nitrogen and heat, and then with water and with carbon dioxide in a condition of expansion.

14. The process which consists in treating dicalcium phosphate with carbonated liine nitrogen, water, and carbon dioxide.

15. The process which consists in treating tricalcium phosphate with carbonated lime nitrogen, water, and carbon dioxide.

16. The process which consists in moistening a pulverized mixture of lime nitrogen and overburned lime, and then treating with carbon dioxide.

Tn testimony whereof, T have signed my name to this specification this 11th day of April, 1917.

LMDIRTEN AUGUST STIILLESEN. 

